JP6985999B2 - Charge protection circuit, charging device, electronic device and charge protection method - Google Patents

Description

The present invention relates to a charge protection circuit, a charging device, an electronic device and a charge protection method.

In the charging device that charges the rechargeable battery (secondary battery), in order to prevent troubles such as overcharging of the rechargeable battery and overheating due to short circuit current, and to charge at a stable voltage, the rechargeable battery is used in the charging circuit. Various security mechanisms are provided to prevent the output of abnormal power. For example, in Patent Document 1, when there is an abnormality in the voltage supplied from the AC adapter, the voltage supplied from the AC adapter is cut off to prevent erroneous charging.

Japanese Unexamined Patent Publication No. 2001-288838

However, the charging device of Patent Document 1 has a problem that it may not be sufficient to deal with an operation abnormality of the charging circuit itself.

An object of the present invention is to provide a charge protection circuit, a charging device, an electronic device, and a charge protection method capable of sufficiently responding to an operation abnormality of the charging circuit.

In order to achieve the above object, the present invention
A switching unit that switches whether or not to energize the charging circuit that supplies power to charge the secondary battery from an external power source,
A detector that detects the current value flowing from the charging circuit to the secondary battery and the voltage value between the two poles of the secondary battery.
A first determination unit that the whether the current value detected by the detection unit is larger than the reference current value, and the said voltage value detected by the detection unit to determine greater or not than the reference voltage value,
When the current value determined by the first discriminating unit is equal to or less than the reference current value and the voltage value determined by the first discriminating unit is larger than the reference voltage value, the charging is performed by the switching unit. A control unit that shuts off the current to the circuit,
A second discriminating unit for determining whether or not the charging circuit is energized from the external power source, and
Based on the discrimination result of the second discrimination unit, the detection cycle for detecting the current value flowing from the charging circuit to the secondary battery and the voltage value between the two poles of the secondary battery is variably set. Detection cycle setting unit and
Equipped with
When the second determination unit determines that the charging circuit is energized by the detection cycle setting unit, the detection cycle setting unit sets a first detection cycle and determines the second determination. When it is determined by the unit that the charging circuit has not been charged from the external power source, or when the power supply to the charging circuit is cut off by the switching unit, the cycle is longer than the first detection cycle. a charge protection circuit, characterized in that you set the second detection period.

According to the present invention, there is an effect that the operation abnormality of the charging circuit can be sufficiently dealt with.

It is a block diagram which shows the functional structure of an electronic device 1. It is a figure which shows the correspondence relationship between the electric power output from a charging circuit, and a control operation. It is a flowchart which shows the control procedure of the charge abnormality monitoring process. It is a block diagram which shows the modification 1 of the functional structure of an electronic device. It is a block diagram which shows the modification 2 of the functional structure of an electronic device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a functional configuration of the electronic device 1 of the present embodiment.

The electronic device 1 includes a charging device 10, a power supply adapter 20, a secondary battery 30, a functional block 40, and the like.

The charging device 10 receives power supplied from an external power source and outputs power to the secondary battery 30 to charge the secondary battery 30.

The power supply adapter 20 converts (AD conversion) the power input from an external power source, here, an AC commercial power source, into a predetermined DC voltage and supplies the power to the charging device 10. The power supply adapter 20 has, for example, a plug for inserting a commercial power supply into an outlet, and automatically starts input / output of electric power when the plug is inserted into the outlet.

The secondary battery 30 supplies the electric power required for the operation of the functional block 40. The secondary battery 30 is a rechargeable battery capable of outputting charged electric power, and is, for example, a lithium ion battery. The secondary battery 30 may be detachable from or detachable from the charging device 10, or may be separate from the charging device 10 and may be replaceable. Alternatively, the secondary battery 30 may be integrally formed with the charging device 10.

The functional block 40 performs each operation of the electronic device 1. The functional block 40 is not particularly limited, but has, for example, a display operation unit, an operation reception unit, and the like, and a liquid crystal display and a touch sensor are provided so as to overlap each other to detect various display operations and external input operations. It may be done. In addition, the functional block 40 may include a measurement unit for measuring physical quantities such as temperature, acceleration, and magnetic field, and an output unit for voice and vibration. Power is supplied to the functional block 40 directly from the secondary battery 30 by wiring (not shown).

Next, the charging device 10 will be described in more detail.
The charging device 10 includes a charging circuit 11, a switching element 12 (switching unit), a current & voltage detection circuit 13 (detection unit), a control unit 14, a resistance element 15, a diode 16, and the like.

The charging circuit 11 outputs a current for charging the secondary battery 30 based on the power from the external power source input from the power supply adapter 20, and supplies the power to be charged to the secondary battery 30. The charging circuit 11 can appropriately convert and output the input DC power (current and voltage). The charging circuit 11 outputs a predetermined current to the secondary battery 30 based on the amount of electricity stored in the secondary battery 30, or outputs a current at about the rated voltage of the secondary battery 30. When the voltage between the two poles of the secondary battery 30 (referred to as the stored voltage) approaches the rated voltage, the current is output at about the rated voltage, and the output current becomes zero when the stored voltage becomes equal to the rated voltage. It becomes. Further, the charging circuit 11 has a conventionally known overcharge prevention circuit in order not to charge the secondary battery 30 above a predetermined upper limit value, and when the storage voltage of the secondary battery 30 reaches the upper limit value. The output of the current from the charging circuit 11 is stopped. After the current output is stopped, the charging operation of the charging circuit 11 is not restarted until the stored voltage becomes less than a predetermined reference value lower than the upper limit value.

The switching element 12 switches whether or not to input the electric power supplied to the charging device 10 to the charging circuit 11. Here, the switching element 12 is, for example, an analog switch, and it is possible to reversibly switch whether or not to energize the charging circuit 11 according to a control signal from the control unit 14. The switching element 12 is normally on, and can be energized in a basic state such as a state in which a control signal from the control unit 14 is not input or a state in which input of a control signal is started (including restart). It becomes a state.

The current & voltage detection circuit 13 includes the output current flowing from the charging circuit 11 to the secondary battery 30, the voltage applied to the secondary battery 30, that is, the magnitude of the current flowing to the secondary battery 30, and the magnitude of the current flowing through the secondary battery 30. The magnitude of the voltage between the two poles (equal to the voltage applied to the secondary battery 30 by the charging circuit 11) is detected, and the signal of the detection result is output to the control unit 14 (detection step). The current & voltage detection circuit 13 may determine whether or not the current or voltage is larger than a predetermined reference value, and output the detection results as binary signals, respectively. Alternatively, the current & voltage detection circuit 13 may acquire (measure) the current value and the voltage value itself and output the current value and the voltage value itself to the control unit 14, and the control unit 14 may compare these values with the reference value. .. The output of the detection result by the current & voltage detection circuit 13 is performed in a predetermined monitoring cycle (first detection cycle), for example, a cycle of 1 second to 10 seconds. The voltage detection by the current & voltage detection circuit 13 may be used not only at the time of charging but also at the detection of the remaining amount of stored electricity due to the discharge of the secondary battery 30. The monitoring cycle (second detection cycle) when charging is not performed may be longer than the first monitoring cycle during charging, and is, for example, 1 minute to 10 minutes here. In this case, the control unit 14 determines whether or not the charging circuit 11 is energized from the external power source via the power supply adapter 20 as the second determination unit. As a detection cycle setting unit, the control unit 14 sets the monitoring cycle to 1 to 10 seconds (first detection cycle) when the charging circuit 11 is energized, and energizes the charging circuit 11. If this is not done (when charging is not performed), the monitoring cycle may be set to 1 minute to 10 minutes (second detection cycle). Whether or not the power supply adapter 20 is energized to the charging circuit 11 may be determined based on the current input from the input end side of the charging circuit 11 to the control unit 14 via the diode 16. Alternatively, a current detection circuit may be separately provided upstream of the charging circuit 11 and the control unit 14 may acquire the result, or a circuit for detecting the presence or absence of energization may be provided in the charging circuit 11 to control the result. The unit 14 may acquire it.
Further, as will be described later, when the control unit 14 detects an abnormality based on the detection result of the current & voltage detection circuit 13 and switches the switching element 12 to the off state (the state in which the energization is cut off), the monitoring cycle is set. You may return to the setting of 1 minute to 10 minutes.

The control unit 14 determines whether or not an abnormality has been detected based on the detection result of the current & voltage detection circuit 13 (operation as a discrimination unit), and the switching state of the switching element 12 (that is, whether or not energization is possible) according to the determination result. To control). As described above, the control unit 14 can switch the switching element 12 to either an on state (a state in which energization is possible) or an off state (a state in which energization is cut off). When the current or voltage is equal to or higher than the reference value based on the detection result, the control unit 14 determines that an abnormality has been detected, turns off the switching element 12, and shuts off the energization, both of which serve as a reference. If it is less than the value, the switching element 12 is turned on. The control unit 14 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), and the like, and operates by receiving power supplied from the power supply adapter 20 or the secondary battery 30 via the diode 16, respectively. Further, the control unit 14 outputs a control signal to the functional block 40 of the electronic device 1 to control the operation. Even when the operation of the functional block 40 of the electronic device 1 is stopped, the control unit 14 may be continuously or intermittently started and operated to continuously charge and monitor the secondary battery 30. Alternatively, the control unit that controls the operation of the functional block 40 may be provided separately from the control unit 14.

Of the above configurations, at least the switching element 12, the current & voltage detection circuit 13, and the control unit 14 constitute the charge protection circuit 10a in the charging device 10 of the present embodiment.

Next, the switching operation control of the switching element 12 by the control unit 14 will be described.
FIG. 2 is a diagram showing a correspondence relationship between the electric power output from the charging circuit 11 and the control operation. It should be noted that the changes in current and voltage shown here, particularly the relationship between the ascending speed and the decreasing speed, are exemplary and do not necessarily reflect specific values.

The power output for charging by the charging circuit 11 is, for example, performed at a constant current when the stored voltage of the secondary battery 30 is low, and is performed at a substantially constant voltage when the stored voltage reaches a predetermined value or higher. In charging at a substantially constant voltage, the current gradually decreases as the stored voltage approaches the constant voltage, and finally the charging current becomes almost zero and charging ends.

As shown in FIG. 2A, during charging power output in a state where the stored voltage V is sufficiently lower than the upper limit value VU, the internal voltage rises above the original set voltage or is short-circuited due to an abnormality in the charging circuit 11 or the like. When the output current Ic increases (timing t1), the rising speed of the stored voltage V continues to increase, and the current exceeding the upper limit IU is detected in the monitoring cycle of the current & voltage detection circuit 13. (Timing t2). When the control unit 14 detects that the output current is larger than the upper limit value IU (reference current value), the control unit 14 switches the control signal S of the switching element 12 from “ON” to “OFF”. As a result, the switching element 12 cuts off the energization and the power supply to the charging circuit 11 is cut off, so that the output current Ic from the charging circuit 11 becomes zero.

As shown in FIG. 2B, when the stored voltage V is high and the output current Ic of the charging circuit 11 increases (timing t1), the stored voltage V reaches the upper limit value VU in a short time. As a result, the overcharge prevention circuit of the charging circuit 11 works, the control signal S is switched to "OFF", and the current output is stopped. After the output current Ic becomes "0", when the stored voltage V gradually decreases due to the power consumption by the control unit 14 or the like and falls below the reference value VL, the current output is restarted, but due to the above abnormality, it is also for a short time. The storage voltage V rises at, and the current output is stopped. That is, the output current Ic has a short pulse-like periodic change, and the stored voltage V of the secondary battery 30 has a sawtooth shape at the same period.

As described above, the current & voltage detection circuit 13 acquires and outputs the detection result in a predetermined monitoring cycle. Therefore, if the output pulse width of the output current Ic is narrow, the monitoring timing does not match and the abnormal current is detected. It may take some time to complete. Here, the charging circuit is charged by setting the monitoring reference value VF (reference voltage) lower than the upper limit value VU and reference value VL of the overcharge prevention circuit (higher than the set voltage at the time of normal approximate voltage charging). When the output from 11 is abnormal, the state in which the stored voltage V exceeds the monitoring reference value VF continues, and the abnormal state is reliably detected. When a voltage larger than the monitoring reference value VF is detected, the control unit 14 switches the switching element 12 to shut off the energization (timing t2).

In this charge protection circuit 10a, whether or not energization by the switching element 12 is switched by the control unit 14, so that when the energization from the power supply adapter 20 is cut off, the power supply to the control unit 14 by the secondary battery 30 is sufficient. It needs to be maintained for a long time. Therefore, when the switching element 12 is cut off from the power supply, the control unit 14 limits the operation other than the switching control of the switching element 12, that is, the operation of the functional block 40, and reduces the power consumption by the functional block 40. .. For example, the display operation unit of the functional block 40 can display an abnormality in the charging device 10 (charging circuit 11), but can limit the upper limit of the brightness of the display. Further, it is possible to prohibit the start of the application program other than the control program related to the basic operation of the control unit 14, or to prompt the user to end the operating application program. On the other hand, the control unit 14 does not have to limit a part of the functional blocks 40, for example, the operation as an operation reception unit, that is, the detection of the input operation and the output of the detection signal to the control unit 14. ..

FIG. 3 is a flowchart showing a control procedure by the control unit 14 of the charging abnormality monitoring process executed by the charging device 10. This charge abnormality monitoring process is started in synchronization with the monitoring cycle in the current & voltage detection circuit 13.

When the charging abnormality monitoring process is started, the control unit 14 acquires the output current Ic and the stored voltage V from the current & voltage detection circuit 13 (step S101). The control unit 14 determines whether or not the output current Ic is larger than the upper limit value IU (step S102). If it is determined that it is larger than the upper limit value IU (“YES” in step S102), the processing of the control unit 14 proceeds to step S104.

When it is determined that the output current Ic is not larger than (or less than) the upper limit value IU (“NO” in step S102), the control unit 14 determines whether or not the stored voltage V is larger than the monitoring reference value VF. Determination (step S103). If it is determined to be large (“YES” in step S103), the process of the control unit 14 shifts to step S104.

When it is determined that the stored voltage V is not larger than (or less than) the monitoring reference value VF (“NO” in step S103), the control unit 14 outputs an on signal that enables the switching element 12 to be energized. Output (step S105). Then, the control unit 14 ends the charging abnormality monitoring process.

When the process of steps S102 and S103 shifts to step S104, the control unit 14 outputs an off signal for shutting off the energization to the switching element 12 (step S104). Then, the control unit 14 ends the charging abnormality monitoring process.
Of these processes, the process of steps S102 and S103 is the operation as the discriminating unit of the present embodiment (discrimination step), and the process of step S104 is the operation of the control unit of the present embodiment (switching step). ..

FIG. 4 is a block diagram showing a modification 1 of the functional configuration of the electronic device 1.

In the electronic device 1, in the charging device 10, a fuse 12a and a switching element 12b are provided as switching portions instead of the switching element 12. The fuse 12a is provided between the power supply adapter 20 and the charging circuit 11, and is blown when a current of a predetermined current value or more flows. The switching element 12b is located between the fuse 12a and the charging circuit 11 and between the ground plane. The switching element 12b is turned on in response to a signal input from the control unit 14 to form a short-circuit path through the fuse 12a from the power supply adapter 20.

When the control unit 14 detects an abnormality from the detection result of the current & voltage detection circuit 13, the control unit 14 turns on the switching element 12b. The fuse 12a is blown by the short-circuit current flowing through the short-circuit path formed thereby, and the supply of electric power to the charging circuit 11 is cut off. That is, once the energization is cut off, the charge protection circuit 10a maintains the cutoff state. In this case, the charging circuit 11 and the fuse 12a may be replaceable, or the entire charging device 10 may be replaced, depending on cost and labor. Alternatively, the entire electronic device 1 may be replaced.

FIG. 5 is a block diagram showing a modification 2 of the functional configuration of the electronic device 1.

The electronic device 1 is provided with a switch 12c having a latch instead of the switching element 12 as the switching unit in the above embodiment. The specific method of the latch is not particularly limited, and when the switch 12c is mechanically switched off by receiving a control signal that turns off from the control unit 14 (cuts off the power supply from the power supply adapter 20), the switch 12c is turned off. Latch (maintain). The off state is released by a reset signal from the control unit 14, or by a manual operation by the user. That is, when it is determined by the control unit 14 that no abnormality is found in the detection result of the current & voltage detection circuit 13, or when the operation of the control unit 14 is stopped and the signal from the control unit 14 is interrupted. , The switch 12c is left in the off state and the energization is not resumed, but the switch 12c itself is not destroyed. Therefore, the switch 12c may be used when the failed charging circuit 11 in the charging device 10 can be replaced.

As described above, the charge protection circuit 10a of the charging device 10 included in the electronic device 1 of the present embodiment is a switching element that switches whether or not to energize the charging circuit 11 that supplies power for charging the secondary battery 30 from an external power source. 12, the current & voltage detection circuit 13 that detects at least one of the current flowing from the charging circuit 11 to the secondary battery 30 and the voltage between the two poles of the secondary battery 30, and the current & voltage detection circuit 13 as a discriminator. A control unit 14 is provided as a switching unit for determining whether or not there is an abnormality in the detection result and, when it is determined that there is an abnormality, the switching element 12 cuts off the energization of the charging circuit 11.
In this way, when an abnormality occurs in the output of the charging circuit 11, it is detected and the power supply itself to the charging circuit 11 is cut off, so that not only the overcharging of the secondary battery 30 is prevented but also charging is performed. The abnormality itself of the circuit 11 can be quickly detected and the operation can be stopped. As a result, troubles due to overheating of each part such as the charging device 10 and the secondary battery 30 can be suppressed.

Further, the switching element 12 is in a state where it can be energized in the basic state. Therefore, it is not necessary to perform the initial setting of the switching element 12 every time when the electronic device 1 or the charging device 10 is started, and the normal charging and power feeding operation can be started promptly.

Further, the control unit 14 controls the operation of the electronic device 1 provided with the charge protection circuit 10a, and as a basic state, the electronic device 1 is in a state where it can be energized when it is started. That is, when the electronic device 1 is started, normally, power can be supplied from both the secondary battery 30 and the power supply adapter 20, and it can be freely switched according to the user's usage state and the like. As long as no abnormality occurs in the device 10, the use of the electronic device 1 is not restricted without making any particular settings.

Further, the charge protection circuit 10a maintains the cutoff state when the current is cut off by the combination of the fuse 12a and the switching element 12b of the modification 1 or the switch 12c of the modification 2. As a result, it is possible to prevent the charging circuit 11 from being supplied with electric power again after the energization is cut off, without performing repairs or the like.

Further, the charge protection circuit 10a of the first modification has a fuse 12a, and the current is cut off by cutting the fuse 12a. By physically disconnecting the wire in this way, it is possible to reliably cut off the energization of the charging circuit 11. In particular, when the abnormality is not repaired but replaced by replacing the charging device 10 or the entire electronic device 1, the energization is completely cut off with such an easy configuration, so that the charging circuit 11 is unnecessary. It is possible to reliably prevent the power from being supplied again and generating heat.

Further, in the charge protection circuit 10a of the second modification, a switch 12c having a latch that holds the cutoff state when the state is switched to the cutoff state is used. In this way, after the energization is cut off, the latch can be reset while maintaining this state to prevent the energization before the charging circuit 11 is repaired or replaced, and the person in charge of repair after the repair is done. A reset operation can be performed to enable reuse of the charging device 10.

Further, the control unit 14 switches whether or not energization is possible by the switching element 12 depending on whether or not an abnormality is detected. As described above, the switching element 12 may be simply switched according to the state of the place only, whereby the energization can be resumed promptly after the charging circuit 11 is restored. On the other hand, even if the charging circuit 11 remains in an abnormal state, the switching element 12 immediately shuts off the energization again immediately, which does not cause a problem.

Further, when the control unit 14 controls the operation of the electronic device 1 provided with the charge protection circuit 10a and the energization is cut off by the switching element 12, at least the operation other than the switching control of the switching element 12 is performed. Restrict some. After the energization from the external power supply is cut off, the electronic device 1 operates depending on the remaining amount of the secondary battery 30, so that the control unit 14 that controls the operation of the switching element 12 by limiting other operations It can be operated for a long period of time.

Further, the current & voltage detection circuit 13 detects the current flowing through the secondary battery 30, and the control unit 14 switches when the current & voltage detection circuit 13 detects a current larger than the upper limit value IU of the current. The element 12 cuts off the current. In this way, by promptly cutting off the energization based on the current before the secondary battery 30 is overcharged, it is possible to suppress heat generation due to a large current and prevent the occurrence of troubles.

Further, the current & voltage detection circuit 13 detects the voltage between the two poles of the secondary battery 30, and the control unit 14 detects a voltage larger than the monitoring reference value VF by the current & voltage detection circuit 13. The switching element 12 cuts off the energization.
When a large current flows due to a short circuit of the circuit, etc., the protection circuit may be activated immediately depending on the voltage and the current output may be cut off. It may not be done. By detecting the voltage level that is lower than the detection of overvoltage and reaches when the current output corresponding to the large current is cut off, even if the large current is cut off, the voltage is exceeded. Since it is possible to detect the generation of a large current, it is possible to more reliably cut off the energization of the charging circuit 11 against an abnormality in the charging circuit 11.

Further, the control unit 14 determines whether or not the charging circuit 11 is energized from the external power source as the second determination unit, and the detection cycle setting unit detects the current and voltage based on the determination result. The detection cycle in which the circuit 13 detects at least one of the current flowing from the charging circuit 11 to the secondary battery 30 and the voltage between the two poles of the secondary battery 30 is variably set.
The current & voltage detection circuit 13 may be used not only for detecting charging abnormality but also for detecting the amount of stored electricity (remaining amount) of the secondary battery 30. By using the same configuration in this way, the size can be increased. Suppress the increase in cost. In this case, an appropriate monitoring cycle may be set according to the difference in changes in current and voltage related to charging and discharging, which can prevent unnecessary processing and increase in power consumption.

Further, when it is determined that the charging circuit 11 is energized from the external power supply, the control unit 14 as the detection cycle setting unit sets the first detection cycle and from the external power supply to the charging circuit 11. If it is determined that the battery is not charged, a second detection cycle longer than the first detection cycle is set. Since the voltage change and the magnitude of the current related to the use of the power supplied from the normal secondary battery 30 do not undergo a sudden change like the detection of a charging abnormality, the power consumption (during discharge) is charged. The detection operation may be performed in a cycle (second detection cycle) longer than the monitoring cycle (first detection cycle) at the time of abnormality detection. As a result, current and voltage can be efficiently detected at a required frequency according to the purpose.

Further, the control unit 14 sets a second detection cycle as a detection cycle setting unit when the energization of the charging circuit 11 is cut off by the switching element 12. That is, when charging is stopped due to a charging abnormality, it is equivalent to normal power consumption. Further, since it may be necessary to continue the operation of the secondary battery 30 for as long as possible without recharging, power consumption can be suppressed by lengthening the monitoring cycle by the above switching setting.

Further, the charging device 10 of the present embodiment includes the charging protection circuit 10a and a charging circuit 11 that receives power from an external power source and supplies electric power to charge the secondary battery 30. As a result, the charge protection circuit 10a reliably detects an abnormality in the charge circuit 11 and cuts off the energization of the charge circuit 11, so that the secondary battery can be charged more safely and quickly.

Further, the electronic device 1 of the present embodiment includes the above-mentioned charging device 10. As a result, troubles such as overheating of the electronic device 1 can be more reliably suppressed, and the electronic device 1 can be safely operated by using the secondary battery 30.

Further, the charge protection method of the present embodiment detects at least one of the current flowing from the charging circuit 11 that supplies the power for charging the secondary battery 30 to the secondary battery 30 and the voltage between the two poles of the secondary battery 30. It includes a detection step, a determination step for determining whether or not there is an abnormality in the detection result in the detection step, and a switching step for cutting off the energization of the charging circuit 11 when it is determined that there is an abnormality. In this way, by blocking the input itself to the charging circuit 11 against the output abnormality of the charging circuit 11, troubles of the charging device 10 and the secondary battery 30 corresponding to the abnormality of the charging circuit 11 are more reliably suppressed. be able to.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, in the above embodiment, both the output current from the charging circuit 11 to the secondary battery 30 and the voltage applied to the secondary battery 30 (storage voltage) are detected, but both are not necessarily detected. You may. The current & voltage detection circuit 13 may detect only the current, and in this case, the current monitoring cycle may be longer than that of the above embodiment. Alternatively, the analog circuit may detect the maximum value within the period and output the detection result based on the maximum value to the control unit 14 at a predetermined monitoring cycle. Alternatively, only the voltage may be detected without directly detecting the current, and in this case, the rate of increase in the voltage may be taken into consideration.

Further, in the above embodiment, the switching element 12 has been described as being normally on, but it may be normally off and need to be changed to the on state by the control of the control unit 14. .. In this case, in the above embodiment, the control unit 14 is started by the power supply from the secondary battery 30, but has a circuit capable of directly supplying power from the power supply adapter 20 to the control unit 14. May be good.

Further, in the above embodiment, the monitoring reference value VF (reference voltage) is set lower than the upper limit value VU and the reference value VL of the overcharge prevention circuit (higher than the set voltage at the time of normal substantially constant voltage charging). However, it may be between the upper limit value VU and the reference value VL. In this case, no abnormality is detected between the time when the stored voltage becomes less than the monitoring reference value VF and the time when the reference value VL is reached and a large current flows again. The relative relationship between the values may be appropriately determined according to the monitoring cycle and the like.

Further, in the above embodiment, the control unit 14 has been described as having a configuration in which the control unit 14 is operated by the CPU in terms of software, but the present invention is not limited to this. A hardware circuit may be used to compare the voltage and current with the monitoring reference value VF and the upper limit value IU, and output a signal according to the comparison result to the switching element 12 or the like.

Further, the charge protection circuit 10a may be externally and independently provided to the charging device 10.

Further, the charging device 10 is not provided in the electronic device 1, but may be an independent charging device.
In addition, specific details such as the configuration shown in the above embodiment, the arrangement of each configuration, and the control content can be appropriately changed without departing from the spirit of the present invention.

Although some embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, but includes the scope of the invention described in the claims and the equivalent scope thereof.
The inventions described in the claims originally attached to the application of this application are described below. The claims described in the appendix are the scope of the claims originally attached to the application for this application.

[Additional Notes]
<Claim 1>
A switching unit that switches whether or not to energize the charging circuit that supplies power to charge the secondary battery from an external power source,
A detector that detects at least one of the current flowing from the charging circuit to the secondary battery and the voltage between the two poles of the secondary battery.
A discriminating unit that determines whether or not there is an abnormality in the detection result of the detection unit, and
A control unit that shuts off the energization of the charging circuit by the switching unit when the discrimination unit determines that the detection result of the detection unit is abnormal.
A charge protection circuit characterized by being equipped with.
<Claim 2>
The charge protection circuit according to claim 1, wherein the switching unit is in a state in which energization is possible in a basic state.
<Claim 3>
The charge protection according to claim 2, wherein the control unit controls the operation of the electronic device provided with the charge protection circuit, and the basic state includes the state at the time of starting the electronic device. circuit.
<Claim 4>
The charge protection circuit according to any one of claims 1 to 3, wherein the switching unit maintains the cut-off state when the state is switched to the cut-off state.
<Claim 5>
The charge protection circuit according to claim 4, wherein the switching unit has a fuse and cuts off the energization by cutting the fuse.
<Claim 6>
The charge protection circuit according to claim 4, wherein the switching unit is a switch having a latch that holds the cut-off state when the state is switched to the cut-off state.
<Claim 7>
The charge protection circuit according to any one of claims 1 to 3, wherein the control unit switches whether or not energization is possible by the switching unit according to the presence or absence of detection of the abnormality.
<Claim 8>
The control unit controls the operation of the electronic device provided with the charge protection circuit, and when the switching unit cuts off the energization, at least a part of the operations other than the switching control of the switching unit is performed. The charge protection circuit according to claim 7, wherein the charge is limited.
<Claim 9>
The detection unit detects the current flowing through the secondary battery and determines the current.
When the detection unit detects a current larger than the reference current value, the discrimination unit determines that the detection result of the detection unit is abnormal.
One of claims 1 to 8, wherein the control unit shuts off the energization by the switching unit when the determination unit determines that the detection result of the detection unit is abnormal. Charge protection circuit described in.
<Claim 10>
The detection unit detects the voltage between the two poles of the secondary battery and
When the detection unit detects a voltage larger than the reference voltage, the discrimination unit determines that the result of the detection unit is abnormal.
One of claims 1 to 9, wherein the control unit shuts off the energization by the switching unit when the determination unit determines that the detection result of the detection unit is abnormal. Charge protection circuit described in.
<Claim 11>
A second discriminating unit for determining whether or not the charging circuit is energized from the external power source, and
Based on the discrimination result of the second discrimination unit, the detection cycle in which the detection unit detects at least one of the current flowing from the charging circuit to the secondary battery and the voltage between the two poles of the secondary battery can be changed. The detection cycle setting unit to be set and
The charge protection circuit according to any one of claims 1 to 10.
<Claim 12>
When the second determination unit determines that the charging circuit is energized from the external power source, the detection cycle setting unit sets the first detection cycle and determines the second determination. 11. The 11. Charge protection circuit.
<Claim 13>
The charge protection circuit according to claim 12, wherein the detection cycle setting unit sets the second detection cycle when the energization of the charging circuit is cut off by the switching unit.
<Claim 14>
The charge protection circuit according to any one of claims 1 to 13.
A charging circuit that supplies power to charge the secondary battery by receiving power from an external power source,
A charging device characterized by being equipped with.
<Claim 15>
An electronic device comprising the charging device according to claim 14.
<Claim 16>
A detection step that detects at least one of the current flowing from the charging circuit that supplies power to charge the secondary battery to the secondary battery and the voltage between the two poles of the secondary battery.
A determination step for determining whether or not there is an abnormality in the detection result in the detection step,
A charge protection method comprising a switching step of cutting off the energization of the charging circuit when it is determined in the determination step that the detection result in the detection step is abnormal.

1 Electronic equipment 10 Charging device 10a Charging protection circuit 11 Charging circuit 12 Switching element 12a Fuse 12b Switching element 12c Switch 13 Current & voltage detection circuit 14 Control unit 15 Resistance element 16 Diode 20 Power supply adapter 30 Secondary battery 40 Function block Ic output Current IU upper limit value S Control signal V Storage voltage VF Monitoring reference value VL Reference value VU Upper limit value

Claims (11)

A switching unit that switches whether or not to energize the charging circuit that supplies power to charge the secondary battery from an external power source,
A detector that detects the current value flowing from the charging circuit to the secondary battery and the voltage value between the two poles of the secondary battery.
A first determination unit that the whether the current value detected by the detection unit is larger than the reference current value, and the said voltage value detected by the detection unit to determine greater or not than the reference voltage value,
When the current value determined by the first discriminating unit is equal to or less than the reference current value and the voltage value determined by the first discriminating unit is larger than the reference voltage value, the charging is performed by the switching unit. A control unit that shuts off the current to the circuit,
A second discriminating unit for determining whether or not the charging circuit is energized from the external power source, and
Based on the discrimination result of the second discrimination unit, the detection cycle for detecting the current value flowing from the charging circuit to the secondary battery and the voltage value between the two poles of the secondary battery is variably set. Detection cycle setting unit and
Equipped with
When the second determination unit determines that the charging circuit is energized by the detection cycle setting unit, the detection cycle setting unit sets a first detection cycle and determines the second determination. When it is determined by the unit that the charging circuit is not charged from the external power source, or when the power supply to the charging circuit is cut off by the switching unit, the cycle is longer than the first detection cycle. charge protection circuit, characterized in that you set the second detection period. The charge protection circuit according to claim 1, wherein the switching unit is in a state in which energization is possible in a basic state. The charge protection according to claim 2, wherein the control unit controls the operation of the electronic device provided with the charge protection circuit, and the basic state includes the state at the time of starting the electronic device. circuit. The charge protection circuit according to any one of claims 1 to 3, wherein the switching unit maintains the cut-off state when the state is switched to the cut-off state. The charge protection circuit according to claim 4, wherein the switching unit has a fuse and cuts off the energization by cutting the fuse. The charge protection circuit according to claim 4, wherein the switching unit is a switch having a latch that holds the cut-off state when the state is switched to the cut-off state. In the control unit, the switching unit determines whether the current value determined by the discrimination unit is equal to or less than the reference current value and the voltage value determined by the discrimination unit is larger than the reference voltage value. The charge protection circuit according to any one of claims 1 to 3, wherein the energization / non-energization is switched. The control unit controls the operation of the electronic device provided with the charge protection circuit, and when the switching unit cuts off the energization, at least a part of the operations other than the switching control of the switching unit is performed. The charge protection circuit according to claim 7, wherein the charge is limited. The charge protection circuit according to any one of claims 1 to 8.
A charging circuit that supplies power to charge the secondary battery by receiving power from an external power source,
A charging device characterized by being equipped with. An electronic device comprising the charging device according to claim 9. A detection step that detects the current value flowing from the charging circuit that supplies power to charge the secondary battery to the secondary battery and the voltage value between the two poles of the secondary battery.
First determination step of the whether the current value detected by the detecting step is larger than the reference current value, and the said voltage value detected by the detecting step to determine greater or not than the reference voltage value,
When the current value determined in the first determination step is equal to or less than the reference current value and the voltage value determined in the first determination step is larger than the reference voltage value, the charging circuit is energized. Switching step to shut off ,
A second determination step for determining whether or not the charging circuit is energized from the external power source.
Based on the discrimination result of the second discrimination step, the detection cycle in which the detection step detects the current value flowing from the charging circuit to the secondary battery and the voltage value between the two poles of the secondary battery is variably set. Detection cycle setting step,
Only including,
In the detection cycle setting step, when it is determined by the second determination step that the charging circuit is energized from the external power source, the first detection cycle is set and the second determination is performed. When it is determined by the step that the charging circuit is not charged from the external power source, or when the energization of the charging circuit is cut off by the switching unit, the cycle is longer than the first detection cycle. A charge protection method comprising setting a second detection cycle.

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